Approximate learning of parsimonious Bayesian context trees

Fuente: arXiv
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Hauptverfasser: Ghani, Daniyar, Heard, Nicholas A., Passino, Francesco Sanna
Format: Preprint
Veröffentlicht: 2024
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author Ghani, Daniyar
Heard, Nicholas A.
Passino, Francesco Sanna
author_facet Ghani, Daniyar
Heard, Nicholas A.
Passino, Francesco Sanna
contents Models for categorical sequences typically assume exchangeable or first-order dependent sequence elements. These are common assumptions, for example, in models of computer malware traces and protein sequences. Although such simplifying assumptions lead to computational tractability, these models fail to capture long-range, complex dependence structures that may be harnessed for greater predictive power. To this end, a Bayesian modelling framework is proposed to parsimoniously capture rich dependence structures in categorical sequences, with memory efficiency suitable for real-time processing of data streams. Parsimonious Bayesian context trees are introduced as a form of variable-order Markov model with conjugate prior distributions. The novel framework requires fewer parameters than fixed-order Markov models by dropping redundant dependencies and clustering sequential contexts. Approximate inference on the context tree structure is performed via a computationally efficient model-based agglomerative clustering procedure. The proposed framework is tested on synthetic and real-world data examples, and it outperforms existing sequence models when fitted to real protein sequences and honeypot computer terminal sessions.
format Preprint
id arxiv_https___arxiv_org_abs_2407_19236
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Approximate learning of parsimonious Bayesian context trees
Ghani, Daniyar
Heard, Nicholas A.
Passino, Francesco Sanna
Computation
Machine Learning
Models for categorical sequences typically assume exchangeable or first-order dependent sequence elements. These are common assumptions, for example, in models of computer malware traces and protein sequences. Although such simplifying assumptions lead to computational tractability, these models fail to capture long-range, complex dependence structures that may be harnessed for greater predictive power. To this end, a Bayesian modelling framework is proposed to parsimoniously capture rich dependence structures in categorical sequences, with memory efficiency suitable for real-time processing of data streams. Parsimonious Bayesian context trees are introduced as a form of variable-order Markov model with conjugate prior distributions. The novel framework requires fewer parameters than fixed-order Markov models by dropping redundant dependencies and clustering sequential contexts. Approximate inference on the context tree structure is performed via a computationally efficient model-based agglomerative clustering procedure. The proposed framework is tested on synthetic and real-world data examples, and it outperforms existing sequence models when fitted to real protein sequences and honeypot computer terminal sessions.
title Approximate learning of parsimonious Bayesian context trees
topic Computation
Machine Learning
url https://arxiv.org/abs/2407.19236